I bought a 1972 manufactured home to work as an insurance adjuster in Phoenix. The old unit was a 3 ton residential model. The old duct was pulled loose in multiple areas the old flex torn, patched and kinked. They capped off an old gas pipe sticking up in the old furnace area and re-sealed the old furnace duct.
Dave Jr., Tony, John, Levi and office staff did excellent re-ducting and install of new 3 ton Frigidaire with a 10 year warranty on the unit, with a WiFi Venstar thermostat App on my smartphone and computer. I had to leave the home to deal with my mother's funeral arrangements. It's good to know whether you are there or not ... they are A++.